Polyacrylamide or polyvinyl polymers and natural gums, like guar gum, have been used for several years as deposition or drift reducing agents. U.S. Pat. No. 5,964,917 has shown the benefits of nitrogenous fertilizers, non-derivatized guar gum, cationic guar gum, and non-cationic guar gum, and mixtures, thereof and a silicone defoamer. One problem of this patented formulation is that it must include a silicone defoamer. Another problem with this formulation is the reliance on nitrogenous fertilizers. This formulation is also restricted unnecessarily to a dry form. The amount of nitrogenous fertilizer required is unnecessarily high with relation to the amount of guar. Finally, this prior art is restricted to using non-derivatized guar gum, cationic guar gum, and non-cationic guar gum, and mixtures, thereof. It would be beneficial to use other less expensive drift control agents or deposition agents.
A product currently on the market contains 1% of a polyacrylamide polymer and roughly 10-20% of ammonia salts (sulfate or carboxylic acid) and 1-2% a silicone defoamer. This product is a liquid and does not perform adequately in some instances due to the low level of polyacrylamide polymer used.
Other liquid products currently available contain 30-35% ammonia sulfate, 1-2% polyacrylamide and a silicone defoamer at 1-3%.
Other dry products currently being marketed have some of the same limitations of the patented product described above. Specifically, these products contain about 1-5% of polyacrylamide or polyvinyl polymers, 90-96% of ammonia salts (Ammonia carboxylate, sulfate and polyacrylate) and 1-2% of a silicone defoamer.
Another liquid product contains 1-2% modified guar gum, 30-35% ammonia sulfate, and no defoamer. A similar product contained the same amounts as this one, but also included 5-10% of diethylene glycol as an anti-freeze.
Another liquid product contains 20-30% ammonia sulfate and water, and in another layer of the liquid, contains aromatic acids and aliphatic petroleum distillates.
Another dry product on the market contains 5-10% of a blend of polyacrylamide polymers and xantham gum, and 90-95% ammonia sulfate and 1-5% silicone defoamer.
In U.S. Pat. Nos. 5,529,975 and 5,525,575, Chamberlain describes the use of oils and water to produce stable dispersions of acrylamide polymers for deposition and drift control.